This invention relates to bulb-type generators, that is, to duct mounted turbine generator assemblies, and in particular it relates to an arrangement for withdrawing the generator rotor for maintenance or repair.
The so-called bulb-type generators, or more commonly bulb generators, are assemblies of a turbine and generator in a generally bulb-shaped housing that is mounted horizontally in a water conducting conduit or duct. The generator may be installed through a hatch in the duct wall normally directly above the generator portion of the housing, that is, the upstream portion of the housing. Once the installation is complete the hatch in the duct wall is covered and the generator access is restricted to an access tower that extends between the bulb-shaped generator housing and the duct wall. The tower is frequently circular in cross-section, and it is smaller than the hatch opening used for installation. As the access tower is in the water path it is desirable to keep it small in size to minimize the disturbance and restrictions of water flow for greater efficiency. When maintenance or repair of the generator rotor assembly or the inside of the stator assembly was required in the past, the generator would have to be dismantled and either removed in sections through the hatch opening or temporarily placed in the water passage.